Nonlinguistic Cognitive Functions of Mandarin Speakers With Poststroke Aphasia

PURPOSE

The purpose of this study was to examine the cognitive functions of Mandarin speakers with poststroke aphasia and to investigate the relationship between nonlinguistic cognitive deficits and the severity of aphasia.

METHOD

Twenty-three adults with aphasia resulting from left-hemispheric stroke and 23 adults matched for age and educational level completed a series of six nonlinguistic cognitive tests measuring nonverbal intelligence, short-term memory, visual selective attention, visual alternating attention, auditory selective attention, and auditory alternating attention. A standardized aphasia assessment (Concise Chinese Aphasia Test [CCAT]) was also conducted to evaluate the severity of aphasia. Data analyses examined cognitive functions by comparing task performance of the two groups and examining the relationship between scores on the cognitive tasks and aphasia severity based on a hierarchical regression analysis.

RESULTS

The aphasia group scored significantly lower than the control group on all nonlinguistic cognitive tasks with large effect sizes (d = 0.95 ~ 1.54). Significant associations between different nonlinguistic cognitive tasks and CCAT subtests were observed. Results from the hierarchical regression analysis showed that auditory alternating attention was the only factor that significantly predicted aphasia severity based on CCAT overall scores after age and education level were taken into account.

CONCLUSIONS

The findings align with prior research observing deficits in nonlinguistic cognition in individuals with aphasia. Implications for clinical practice and future research are discussed.

The role of gender in cognitive outcomes from stroke

OBJECTIVE

Stroke can cause cognitive impairment, which can lead to challenges returning to day-to-day activities. Knowing what factors are associated with cognitive impairment post-stroke can be useful for predicting outcomes and guiding rehabilitation. One such factor is gender: previous studies are inconclusive as to whether gender influences cognitive outcomes post-stroke. Accounting for key variables, we examined whether there are gender differences in cognitive outcomes after stroke.

METHOD

We analyzed data from neuropsychological assessments of 237 individuals tested in the chronic epoch (≥ 3 months) following ischemic stroke. Using ANCOVA and linear mixed modeling, we examined gender as a predictor of cognition as measured by general cognitive ability (g), Full-Scale IQ, and 18 cognitive tests, controlling for age at stroke onset, education, premorbid intelligence, and lesion volume.

RESULTS

There were no significant gender differences in overall cognitive outcomes as measured by g (p = .887) or Full-Scale IQ (p = .801). There were some significant gender differences on specific cognitive tests, with women outperforming men on scores from the Rey Auditory Verbal Learning Test (ps < .01) and men outperforming women on the Wechsler Adult Intelligence Scale Arithmetic and Information subtests (ps < .01).

CONCLUSIONS

Our findings indicate that men and women have similar overall cognitive outcomes after stroke, when demographic and lesion factors are accounted for. Although men and women differed in their performance on some individual cognitive tests, neither gender performed systematically better or worse. However, for learning, working memory, and verbal knowledge/comprehension, gender may be an important predictor of outcome post-stroke.

Perilesional and contralesional brain activations related to associative encoding of unfamiliar face-names pairs in adults with left chronic stroke with or without ischemic infarct on left inferior frontal gyrus

The study of an Ischemic stroke infarction allows verifying how the lesion produces alterations in the neuronal networks resulting in cognitive deficits. It also allows the verification of adaptive and maladaptive cerebral reorganization related to the injury. In our previous fMRI study, we found that patients without ischemic vascular lesions in left inferior frontal gyrus showed an efficient compensation mechanism during the associative encoding of face name pairs, by the increased activation of ventrolateral and dorsolateral areas of contralesional hemisphere associated with better memory performance. While patients with ischemic vascular lesions on left inferior frontal gyrus (IFG) demonstrated worse memory performance and no signs of compensation mechanism. The present study explores more of these findings by analyzing perilesional and contralesional activations related to unfamiliar face name associative encoding in adults with chronic ischemic stroke, with or without left IFG lesion, compared to healthy controls. The main results showed that stroke survivors without lesions in IFG demonstrated increased activation in perilesional and contralesional prefrontal regions associated with better associative memory recognition, which are indicative of adaptive compensatory mechanisms. However, they also showed a negative correlation between the activation of right anterior prefrontal and inferior parietal regions and the associative memory performance, which may indicate the presence of maladaptive interhemispheric disinhibition. On the other hand, stroke survivors with IFG lesions demonstrated negative correlations in activations of the ipsilesional inferior parietal cortex and positive correlations in activations of the left middle frontal gyrus and left precentral cortex, which demonstrate the simultaneous occurrence of adaptive and maladaptive brain reorganization mechanisms in this group. However, the increase in perilesional prefrontal regions, associated with bilateral activation of the hippocampus and amygdala, was not enough to compensate for the inefficiency of associative memory performance. Finally, the differences in activation observed in stroke survivors reflect their clinical heterogeneity and demonstrate that adaptive or maladaptive compensatory mechanisms can coexist in the same group of patients. Furthermore, they reinforce the importance of the left IFG in the associative encoding of unfamiliar face name pairs and may suggest a deficit in associative memory related to injury in this region.

Moving Toward Accurate Assessment of Working Memory in Adults With Neurogenically Based Communication Disorders

Purpose This article presents a viewpoint highlighting concerns regarding currently available assessments of working memory in adults with neurogenic communication disorders. Additionally, we provide recommendations for improving working memory assessment in this population. Method This viewpoint includes a critique of clinical and experimental working memory tests relevant to speech-language pathologists. We consider the terminology used to describe memory, as well as discuss language demands and test construction. Results Clinical and experimental testing of working memory in adults with neurogenic communication disorders is challenged due to theoretical, methodological, and practical limitations. The major limitations are characterized as linguistic and task demands, presentation and response modality effects, test administration, and scoring parameters. Taking these limitations into consideration, several modifications to working memory testing and their relevance to neurogenic populations are discussed. Conclusions The recommendations provided in this article can better guide clinicians and researchers to advocate for improved tests of working memory in adults with neurogenic communication disorders. Future research should continue to address these concerns and consider our recommendations.

Examining the Cognitive Proficiency Index in rehabilitation patients

This study examined the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) Cognitive Proficiency Index (CPI) in relation to other WAIS-IV indices, overall test battery mean (OTBM), and impairment (IMP) in an outpatient rehabilitation setting. Participants (N = 329) were 35% female and 88% Caucasian with average age and education of 42.9 (SD = 13.5) and 13.6 (SD = 2.4) years, respectively. Participants were grouped by diagnosis and validity: traumatic brain injury (TBI; n = 176; 39% mild), cerebrovascular accident (CVA; n = 52), other neurologic and psychiatric conditions (OTH; n = 49), and questionable performance validity (QPV; n = 52). OTBM was calculated from non-WAIS-IV tests; IMP was dichotomously defined as four or more non-WAIS-IV scores below cutoff (≤35 T). Significant group differences were observed on CPI, WAIS-IV indices, OTBM, and IMP. CPI significantly contributed (β = .51) to a linear regression model predicting OTBM (R² = .63) with education and GAI as covariates. A logistic regression model with IMP as the outcome and education, GAI, and CPI as predictors correctly classified 80% of cases with area under the curve of .86. A previously identified cutoff (CPI < 84) correctly classified 65-78% of clinical groups categorized by IMP. A novel cutoff (CPI ≤ 80) differentiated clinical participants with history of mild TBI from the QPV group with sensitivity of 44.2% and specificity of 89.7%. CPI showed incremental validity in predicting OTBM and IMP and warrants further study as a useful clinical addition to other WAIS-IV indices.